Hydroxy deuterated

Proton-decoupled C-n.m.r. spectra of partially hydroxy-deuterated carbohydrates show signals in which the multiplicities depend on the environment of the hydroxy group. Five types of multi-plet were identified as being characteristic, e.g., C-6 of a hexo-pyranose gives a broad doublet, while C-1 of a glycoside gives a narrow doublet, etc. The ring sizes of benzoylated L-rhamnono-lactones as determined by C-n.m.r. spectroscopy are discussed in Chapter 16. 

Deuteration of C-methyl protons in simple methylpyrimidines and their amino and hydroxy derivatives has been studied under acidic and basic conditions. The exchange is acid/base catalyzed with, for example, a minimal rate at pH 4 for 1,4,6-trimethylpyrimidin-2(lH)-imine (67JCS(B)171). 

Pyrazolino[2,3-c][l,2,3]triazoles, 5, 702 Pyrazolium hydroxide, l,2-dimethyl-3,5-diphenylanhydro-4-hydroxy-IR spectra, 5, 201 Pyrazolium salts dequatemization, 5, 269 H NMR, 5, 185 hydrogen exchange at ring carbon, 5, 245 mesoionic compounds, 5, 171 nitrodebromination, 5, 237 reactivity, 5, 217 reduction, 5, 68, 243 synthesis, 5, 156 UV spectra, 5, 199 Pyrazolium salts, amino-reactions, 5, 262 Pyrazolium salts, bromo-nucleophilic displacements, 5, 266 Pyrazolium salts, 1,2-dimethyl-deuteration, 5, 175, 245 hydrogen exchange, 5, 71 acid-catalyzed, 5, 239 reactions... 

Thiazolo[3,2-a]pyridinium hydroxide, anhydro-8-hydroxy-2,3-dihydro-deuteration, 6, 702-703 oxidation, 6, 700-701 pK, 6, 682... 

Deuteration of 3 -Hydroxy-5a-androstan-7-one at C-6 and C-8 by Exchange with Deuterium Oxide-5% Sodium Deuterioxide in Methanol-OD... 

Deuteration by cyclopropyl ring opening Ijas been used also for the stmcture elucidation of a photolysis product (241) of cholesta-3,5-diene. This bicyclobutyl derivative is very reactive and readily hydrolyzed by aqueous dioxane. When the ring opening is carried out in the presence of deuterium oxide, a deuterium is incorporated in the 4y -position of the resulting 6jS-hydroxy-3a,5a-cyclocholestane (242). ... 

Bromination of 3 -hydroxy-B-homo-5a-cholestan-7-one acetate (54b) in the presence of hydrobromic acid gives a single thermodynamically stable monobromo ketone. To determine the position of the bromine atom, the sequence of reactions was repeated with compounds selectively deuterated in the 5a-position. 

Quinoxalin-2-ones are in tautomeric equilibrium with 2-hydroxy-quinoxalines, but physical measurements indicate that both in solution and in the solid state they exist as cyclic amides rather than as hydroxy compounds. Thus quinoxalin-2-one and its A -methyl derivative show practically identical ultraviolet absorption and are bases of similar strength. In contrast, the ultraviolet spectra of quinoxalin-2-one and its 0-methyl derivative (2-methoxyquinoxaIine) are dissimilar. The methoxy compound is also a significantly stronger base (Table II). Similar relationships also exist between the ultraviolet absorption and ionization properties of 3-methylquinoxalin-2-one and its N- and 0-methyl derivatives. The infrared spectrum of 3- (p-methoxy-benzyl)quinoxalin-2-one (77) in methylene chloride shows bands at 3375 and 1565 cm" which are absent in the spectrum of the deuterated... 

The alcohol 3) , 28-diacetoxy-6 -hydroxy-18i -12-oleanene was oxidised in an aqueous acetic acid medium Deuteration at the six position had no effect on the rate in solvents of high (> 80 %) acetic acid content, but the isotope effect reached 2 in 60 % acetic acid. Increasing the acetic acid content of the medium produced a much larger effect on the oxidation rate of cyclohexanol than of the polycyclic alcohol. 

The equatorial allylic alcohol 3)S-hydroxyandrost-4-ene is oxidised by Cr(Vl) 310 times faster than the saturated 3)3-hydroxy-5a-androstan-17-one, 5.7 times faster than the axial 3a-hydroxyandrost-4-ene and 6.9 times faster than its 3-deuterated analogue . The greater speed of oxidation of the equatorial isomer is in contrast to the pattern observed for saturated alcohols and probably arises from resonance between the double bond and the incipient carbonyl group. 

Kemp and Waters found a primary kinetic isotope effect of 8.7 for oxidation of C-deuterated mandelic acid and noted a large difference in rate between the oxidations of mandelic acid k at 24.4 °C = 1.7 l.mole . sec ) and a-hydroxy-isobutyric acid ( 2 at 24.4 °C = 5.6 x 10 l.mole . sec ) — a difference not reproduced for the oxidation of these compounds by the one-equivalent reagent, manganic sulphate. The various data are fully in accord with a Westheimer-type mechanism, viz. 

Recently, the mechanism of 6-nitro-BaP ring hydroxylation has been elucidated by using 3-deutero-6-nitro-BaP (144). When incubated with 3-methylcholanthrene-induced rat liver microsomes, this deuterated analogue yielded the same metabolite profile previously observed with 6-nitro-BaP. Spectroscopic analysis of 3-hydroxy-6-nitro-BaP and 6-nitro-BaP-3,9-hydroquinone indicated that 30% of the deuterium label had migrated to carbon 2, presumably via an NIH shift. Therefore, it appears that 6-nitro-BaP-2,3-oxide is a common intermediate for these two metabolites. 

Partial reduction of polyarenes has been reported. Use of boron trifluoride hydrate (BF3 OH2) as the acid in conjunction with triethylsilane causes the reduction of certain activated aromatic systems 217,262 Thus, treatment of anthracene with a 4-6 molar excess of BE3 OH2 and a 30% molar excess of triethylsilane gives 9,10-dihydroanthracene in 89% yield after 1 hour at room temperature (Eq. 120). Naphthacene gives the analogously reduced product in 88% yield under the same conditions. These conditions also result in the formation of tetralin from 1-hydroxynaphthalene (52%, 4 hours), 2-hydroxy naphthalene (37%, 7 hours), 1-methoxynaphthalene (37%, 10 hours), 2-methoxynaphthalene (26%, 10 hours), and 1-naphthalenethiol (13%, 6 hours). Naphthalene, phenanthrene, 1-methylnaphthalene, 2-naphthalenethiol, phenol, anisole, toluene, and benzene all resist reduction under these conditions.217 Use of deuterated triethylsilane to reduce 1-methoxynaphthalene gives tetralin-l,l,3-yielding information on the mechanism of these reductions.262 2-Mercaptonaphthalenes are reduced to 2,3,4,5-tetrahydronaphthalenes in poor to modest yields.217 263... 

A second example can be found in the metabolism of the male sex steroid hormone testosterone. In addition to 7a -hydroxy- and 6a-hydroxytestosterone, CYP2A1 was also found to form A6-testosterone (136) (Fig. 4.69). Using selectively deuterated analogs (136), A6-testosterone was established as being formed in competition with 6o -hydroxytestosterone after initial hydrogen atom abstraction from C6 to form the common radical intermediate. Little, if any, A6-testosterone was found to be formed in competition with la-hydroxytestosterone after initial hydrogen abstraction from Cl. 

The nature of the bonds between cellulosic fibres in paper has been the subject of some controversy over many years. The early and now largely discredited view was that paper derived its strength merely from mechanical entanglement of the fibres. However, experiments in which paper is formed from non-aqueous solvents produce sheets with very poor strength properties and have thus tended to disprove this conjecture. In the mid-1950s deuteration experiments were carried out which demonstrated that of the order of 0.4-2% of all hydroxy groups are additionally bonded in paper as compared with the unbonded fibres. This observation led to the view that... 

As can be seen, the pathway from the cyclohexadienone to the ortho-rearranged phenol does not imply a jump over an energy barrier (34 kcal/mol), but a tunneling from the vibrational energy levels located at E(vo) = 0 kcal/mol and E(vi) = 3.9 kcal/mol (4.4 kcal/mol for the deuterated compound). Analogous results have been reported for the photo-Fries rearrangement of 2,4-dimethoxy-6-( ara-tolyloxy)-v-triazine (28) to give 2,4-dimethoxy-6-(2-hydroxy-5-meth-ylphenyl)-v-triazine (29) (Scheme 11) [43]. 

For other chiral reagents and application of this method to other classes of compounds, such as a-amino esters, a-hydroxy esters, amino alcohols, chiral a-deuterated benzylamine, phosphorus compounds, and the use of nuclei other than hydrogen (l3C, 19F), see reference 186 and Section D.4.1. 

The majority of the more than 100 odorants (reviewed in [1]) synthesised for use as internal standards are labelled with deuterium. However, during the quantification procedure some deuterated odorants might undergo deuterium-protium exchange, which would falsify the results. Examples are 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) [68, 69] and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon) [70], which are consequently labelled with... 

The protons of the hydroxy groups were deuterated by dissolving BP(OH)2 in cyclohexane and shaking the solution with deuterated water for several hours. After precipitation pump-probe measurements of BP(OD)2 in cyclohexane were recorded and are compared to BP(OH)2 in Fig. 4. Both samples were excited at 350 nm and probed at 505 nm. The delay of the emission rise of about 50 fs is equal in both cases and the coherent excitation of the vibrations is identical with respect to frequencies, phases and amplitudes. The ESIPT dynamics is obviously not altered by the deuteration and the mass of the proton has no influence on the transfer speed. This excludes that tunneling of the proton determines the speed of the transfer and the measurements provide the first proof for the passive behavior of the proton in the ESIPT. 

The major pathways for the fragmentation of kojic acid (81,5-hydroxy-2-hydroxymethyl-pyran-4-one), are shown in Scheme 14 support for each route was provided by the appearance of metastable ion peaks (67MI22203). An RDA cleavage followed by loss of a CH2OH radical produces ion (81a), m/e 69, the structure of which was substantiated by deuteration experiments. The ion at m/e 97 arises by extrusion of CO from the molecular ion and loss of HO- from the side chain structures (81b) and (81c) were proposed. Decomposition of [M]t occurs to give ethylene and an HC=0 fragment. The initial stage involves loss of a -CHO radical from the hydroxymethyl substituent, a process which has... 

Hydrodesulfurization of certain hydroxy-437 and methoxy-sub-stituted615 alkybenzo[6]thiophenes is a useful means of preparing some otherwise inaccessible alkyl-substituted phenols [e.g., Eq. (15)].015 Various p-methoxyphenylbenzo[6]thiophenes have been employed similarly to prepare the corresponding hydroxydiphenyl-alkanes.464 Catalytic hydrodesulfurization of a-alkyl-/ -(3-benzo[6]-thienyl)propionic acids affords a convenient method of preparing a,y-disubstituted y-phenylbutyric acids.636 Treatment of / -(3-benzo[6]thienyl)acrylic acid with Raney nickel alloy, sodium meth-oxide, and deuterium oxide affords the deuterated acid (366).667... 

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